I find evil characters to be weird although most of the time, it's to do with how it's played out. It's especially annoying when these evil characters have a family which are somehow invincible because they're nearby (and i am referrencing someone who regulars the Temple of Dreams here) and is an all powerful being who hears everything, see's everything etc.
My character, Martok (created after my first, Sarkardo, died saving a friend (yes, i do RP death) after getting massive burns by jumping through a closing portal) is semi-evil in that his powers are evil, the power of physical entity manipulation so he can move stuff, change its size, shape, density etc and basically kill very quickly, and very slowly but he needs to see the target (the limitation I created so he isn't some uber powerful wolf), but once you get past his hard outer shell of 'oh...hi, what you want' etc, he's a really nice character and if you REALLY earn his trust, he will give his life to save yours if needed, like he did last night or at least, almost gave his life but saved the life of his now mate. However, he avoids killing and usually just maims to incapacity and then leaves then or helps them a bit so they don't die.